UPGRADING AND RECYCLING OF PRINTED CIRCUIT BOARD

UPGRADING AND RECYCLING OF PRINTED CIRCUIT BOARD

Detalles del proyecto

Coste total:

No disponible

Aportación de la UE:

No disponible

Coordinado en:

Netherlands

Tema(s):

Régimen de financiación:

CSC - Cost-sharing contracts

Objetivo

A project was initiated to develop an upgrading and recycling process for printed circuit board (PCB) fractions and moulded interconnection devices (MID) fractions directed towards an automation process. This included investigation of preprocessing, chemical processing, shredding, and physical/mechanical final processing. A representative selection of available boards was made. Analysis showed that composition can vary a lot. For this reason a database concept has been designed in which the available information can be represented for either a mean component (eg resistor, capacitor) and/or detailed representation of specific components. The database design has been finalized and a prototype is available.

Because of the large differences in composition of the different components new methods had to be developed for the removal of the components. The combination of heating (infrared, vapour phase, direct heating) and mechanical operation seemed a favourable option. The solder tear off process of different components was analyzed. A prototype was constructed to realize the thermal/mechanical separation of surface mount device (SMD) components and MID/PCB by air pressure. Experiments have been realized on the techniques resulting from an inventory study. Selection and development of physical mechanical and physical chemical separation techniques were pursued in order to upgrade the disassembled fractions and to make these fractions suitable for secondary raw material. A study has been carried out on the stripping of the metal surface layer of MID's. Some possibilities of the metal recovery have been investigated. Interdependencies of the strip process parameters were worked out; relations between sort of acid, acid concentration, sort and amount of oxidation agent, temperature and hydrodynamics were given. For metal recovery, membrane electrolysis and diffusion processes have been investigated. A study has been carried out on the separation of a sample of PCB's containing large objects like transformers. After fragmentation analysis showed that some fractions are potentially interesting for chemical processing, and that for other fractions further mechanical upgrading could be effective.CURRENTLY THE PRINTED CIRCUIT BOARD (P.C.B.) FRACTION FROM ELECTRIC AND ELECTRONIC EQUIPMENT (SUCH AS AUDIO/VIDEO EQUIPMENT AND PERSONAL COMPUTERS) IS HARDLY BEING RECYCLED AFTER THE EQUIPMENT HAS BEEN DISCARDED. IT IS ASSUMED THAT THIS WILL HAPPEN IN THE FUTURE, IN ORDER TO PREVENT AND REDUCE ENVIRONMENTAL HARM. AFTER CHANGES IN THE COLLECTION STRUCTURE, THE PROCESSING OF CONSIDERABLE QUANTITIES OF ELECTRIC/ELECTRONIC EQUIPMENT AND PRINTED CIRCUIT BOARD FRACTIONS SEPARATED FROM IT IS EXPECTED. THE WAY OF PROCESSING IS DETERMINED, AMONG OTHER THINGS, BY THE ECONOMIC SCALE AND THE PROCESSING METHOD CHOSEN. APART FROM THIS, THE TECHNOLOGICAL DEVELOPMENT IN THE CONSTRUCTION OF PRINTED CIRCUIT BOARDS PLAYS AN IMPORTANT ROLE. THIS COULD INVOLVE THAT IT IS NECESSARY TO CHANGE THE PROCESSING FOR THE VARIOUS PRINTED CIRCUIT BOARD FRACTIONS FROM DIFFERENT PERIODS. AN IMPORTANT ASPECT TO BE INVESTIGATED IN THIS RESPECT IS WHETHER THERE IS A TENDENCY TOWARDS AN INCREASE IN RECYCLING POSSIBILITIES (UPGRADING) OF PRINTED CIRCUIT BOARD FRACTIONS. THE AIM OF THE PROJECT IS TO DEVELOP AN UPGRADING AND RECYCLING PROCESS (OR PROCESSES) FOR PRINTED CIRCUIT BOARD FRACTIONS (FOR FRACTIONS FROM DIFFERENT PERIODS AND/OR FRACTIONS FROM DIFFERENT EQUIPMENT GROUPS), THAT IS DIRECTED TOWARDS AN AUTOMATION PROCESS, MEANING A MINIMUM OF MANUAL EFFORT.

ESSENTIAL STEPS TO BE INVESTIGATED ARE: * PREPROCESSING STEP; SEPARATION OF ELECTRONIC COMPONENTS BY MEANS OF SELECTIVE DISMANTLING * GALVANIC STEP; REPROCESSING OF THE PRINTED CIRCUIT BOARDS AFTER THE ELECTRONIC COMPONENTS HAVE BEEN REMOVED * SHREDDING STEP; SELECTIVE SHREDDING OF MIXTURES OF ELECTRONIC COMPONENTS * PHYSICAL/MECHANICAL FINAL PROCESSING STEP; CONCENTRATION OF THE METALS AFTER SHREDDING. INNOVATIVE ASPECTS OF THE RESEARCH ARE: * THE PROCESS TO BE SET UP IS BASED ON SELECTIVE DISMANTLING AND REVERSE ASSEMBLY *ON THAT BASIS, ALTERNATIVE RECYCLING SYSTEMS WILL BE DEVELOPED * THE PROCESS (PROCESSES) DEVELOPED WILL BE AUTOMATED AS MUCH AS POSSIBILE * ADVICE AS TO THE DESIGN OF PRINTED CIRCUIT BOARDS SO THAT THEIR FUTURE RECYCLING WILL BE REALIZED WITHIN ECONOMIC AND ENVIRONMENTAL LIMITING CONDITIONS * APPLICATION OF THE DEVELOPED PROCESS WILL LEAD TO AN APPARENT INCREASE IN RECYCLING, A DECREASE IN RESIDUE QUANTITY, AS WELL AS A DECREASE IN THE POTENTIAL ENVIRONMENTAL HARM OF THE REMAINING RESIDUES.